Does endurance training prior to ovariectomy protect against myocardial contractility dysfunction in rats?

Abstract

Endurance training prevents cardiac dysfunction induced by menopause, but to date, no studies compared the effects of endurance training prior to menopause versus estrogen replacement therapy during menopause on heart function of rats. Female Wistar rats aged three months were randomly assigned into three groups: Untrained ovariectomized rats (UN-OVX), untrained ovariectomized rats treated with estradiol (UN-OVX-E2), and ovariectomized rats previously exercised (EX-OVX). The endurance training protocol consisted of running on a treadmill at 60-70% of maximal aerobic capacity, 60min per day, five days per week, for eight weeks. Estradiol replacement therapy consisted of silastic capsules containing the hormone for twelve days. After euthanasia, hearts were harvested, weighed and cardiac function was evaluated by the Langendorff technique. Both cardiac contractility and relaxation indexes improved similarly in the EX-OVX and UN-OVX-E2 rats compared to UN-OVX. Our findings reveal similar beneficial effects between endurance training previously to menopause and estradiol replacement therapy during menopause on cardiac function of rats.